FIELD OF THE INVENTION
The invention relates to a device for driving at least one capacitive actuator, in particular a piezoelectrically operated fuel injection valve of an internal combustion engine, by a control circuit. The invention also relates to a method for operating the device.
Published, European Patent Application EP 0 464 443 A1 discloses a piezo actuator which is charged from a capacitor via a charge coil. A portion of the energy applied is fed back into the capacitor via a discharge coil during the discharging of the piezo actuator, while the last portion is destroyed by short-circuiting, likewise via the discharge coil. During the discharging, a negative voltage is applied to the piezo actuator.
Published, Non-Prosecuted German Patent Application DE 36 21 541 A1 discloses a driver circuit for a piezo actuator of a fuel injection valve which is charged via a series circuit, connected to a voltage source and includes two capacitors, and via a charge coil, and is discharged into one of the two capacitors via a discharge coil. In an alternative embodiment, the actuator is charged via a capacitor, connected to a voltage source, and a charge coil. During the discharging, the energy stored in the piezo actuator is destroyed via a discharge coil.